Core making apparatus



y 6, 1965 H. L. M CORMICK 3,192,578

CORE MAKING APPARATUS Original Filed June 8. 1960 4 Sheets-Sheet 1 INVEN TOR.

ATTORNEY CORE MAKING APPARATUS Original Filed June 8, 1960 4Sheets-Sheet 2 ATTORNEY 4 Sheets-Sheet 5 INVENTOR. Ami/zmf WNW/7212iATTORNEY July 6, 1965 H. L. MCCORMICK I CORE MAKING APPARATUS OriginalFiled June 8, 1960 4 Sheets-Sheet 4 Original Filed June 8. 1960 nitedStates Patent 3,192,578 f AKIR G AIFARATUS Hamilton L. McCormick,(Iarinel, Ind, assigns-rto General Motors @orporation, Detroit, Mich, acorporation of Delaware Uriginai application June 8, E69, Ser. No.34,792.

Bivided and this application Aug. I7, I961, er.

illairns. (Cl. 22-143) This application is a division of the co-pendingpatent application Serial No. 34,792, filed June 8, 1960, now abandoned,and assigned to the assignee of the present invention.

This invention relates to hollow turbine blades and vanes, entranceguide vanes and the like which have fluid passages therethrough toprovide means for cooling the blade during the operation of the enginein connection with which it is used, and a method and apparatus formaking the same.

In turbojet engines or the like a turbine operated by burning gasesdrives a blower which furnishes air to a burner. Such turbines operateat high temperatures and the capacity of the engine is in part limitedby the ability of the metal of which the turbine blades are made towithstand the high operating temperatures. One approach to increasingthe operating temperature of these engines involves providing the bladeswith cooling means in the form of openings through the airfoil of theblade through which a coolant fluid such as air may be passed duringoperation of the engine. Casting blades of this type involves diflicultfoundry problems because the airfoil of the blades is relatively thinand may involve a markedly curved configuration. Moreover, the coolantpassages must be accurately positioned within the blade so as to enablethe coolant gas to perform its desired function and et be designed so asnot to weaken the blade.

It is the basic object of this invention to provide a unitarily castturbine blade, vane and the like having coolant passages extendingthrough the airfoil thereof by means of which the airfoil may beefficiently cooled and having a structure which is sufficiently sturdyto withstand the forces imposed on the blade during operation of theengine in connection with which it is used. To this end, a hollow blade,vane or the like is cast which has a plurality of internal ribsextending longitudinally of the blade and projecting inwardly of eachairfoil wall toward the interior of the blade and a plurality ofintegrally cast supports or pedestals extending between the airfoilwalls. The internal ribs serve to efficiently transfer heat from theairfoil surfaces into the air coolant passage whereby the blade isefiiciently cooled and the integral support members serve to bothrigidity the blade structure and also to transfer heat from the airfoilsurfaces into the coolant passage.

It is a further object of this invention to provide a method of castinga hollow blade or the like having opposed airfoil walls, a plurality ofspaced ribs extending from each of the airfoil walls inwardly thereofand a plurality of spaced pedestals or supports extending transverselyof the blade and connecting the opposed airfoil walls.

Another object of this invention is to provide a core for use in theaforementioned method and to provide mold apparatus for making the core.

These and other objects are accomplished by providing a destructibleceramic core which has the general configuration of the vane or turbineblade to be cast including an airfoil portion having opposed concave andcon vex airfoil surfaces. A plurality of spaced parallel grooves areprovided in each airfoil wall longitudinally dddzjlh Patented July 6,1965 "ice thereof and a plurality of spaced transverse openings areprovided through the airfoil portion of the core. The core ismanufactured by an injection die apparatus which includes a mold cavityhaving the configuration of the core to be formed. The apparatusincludes a plurality of spaced retractable fins which are adapted toproject into the die cavity a predetermined distance from opposed wallsof the die cavity. The apparatus also preferably includes spacedextensions on certain of the opposed fins which engage opposed fins whenthe fins are inserted within the die cavity. In manufacturing the core,a suitable ceramic mix is injected into the mold cavity while theaforesaid fins project into the die cavity and the aforesaid extensionsengage at least one tin member on the opposite side of the die cavity.After the die cavity has been filled with the ceramic mix, thelongitudinal fins together with the fin extensions are retracted fromthe die cavity. The thusly formed core is then dried and fired. A heatdestructible pattern is then formed about the ceramic core whichcorresponds in its outer configuration to the out-er configuration ofthe blade to be cast and this pattern is then invested in a refractorymold. After the refractory mold has been set, it is fired whereby theheat destructible Portion of the pattern is melted out and the core isleft supported within the resulting mold cavity by suitable core prints.Molten metal is then cast into the resulting mold cavity about theabove-described core. The core is then leached.

out or otherwise removed from the casting to form a hollow blade havinga plurality of spaced longitudinal ribs extending inwardly from each ofthe airfoil walls and a plurality of transverse pedestals or supportsintegrally attached to the opposed airfoil walls. The pedestal orsupport portions of the blade extending transversely therethroughprovide the blade with a high degree of structural strength while thelongitudinal fins extending inwardly of the airfoil walls provide ahighly efiicient means for transmitting the heat from the workingsurfaces of the airfoil walls into the interior hollow portion thereofthrough which a coolant fluid is passed in the operation of the enginein connection with which the blade is used.

Other objects and advantages of this invention will more fully appearfrom the following detailed description, reference being made to theaccompanying drawings, in which:

FIGURE 1 is an elevation view of a turbine blade;

FIGURE 2 is a cross-sectional view taken along line 2-2 of FIGURE 1;

FIGURE 3 is an elevation view of a core used in the casting of theturbine blade shown in FIGURE 1;

FIGURE 4 is a cross-sectional View taken substantially along line d-4 ofFIGURE 5;

FIGURE 5 is a cross-sectional view taken along line 5-5 of FIGURE 3;

FIGURE 6 is an elevation view of a die apparatus for molding the core ofFIGURE 3 which is shown in die open position;

FIGURE 7 is an elevation view of the die apparatus shown in a die closedposition;

FIGURE 8 is a view taken along line 8-8 of FIGURE 7, the parting line ofthe die;

FIGURE 9 is an elevation side view of the die apparatus of FIGURE 6shown in a die open position; and

FIGURE 10 is a cross-sectional view taken along line Iii1 of FIGURE 8.

Referring more particularly to the drawings, FIGURES l and 2 show aunitarily cast turbine blade of the present invention. The bladeincludes an airfoil portion 19 having a longitudinal passage 11therethrough, a platform portion 12, a stalk or shaft portion 14, and aroot portion 16. As shown in FIGURE 2, the airfoil portion of the bladeis hollow and has a concave wall portion 18 and a convex wall portionwhich surround the passage 11. The concave wall portion 18 has aplurality of longitudinal ribs or fins 19 projecting from the inner wallthereof into the interior of the blade. Similarly, the concave wallportion 26 has a plurality of spaced longitudinal ribs or fins 21projecting from the inner surface thereof toward the interior of theblade. The airfoil portion 10 also includes a plurality of integrallycast pedestals or supports 22 extending from the concave airfoil wallportion 13 to the convex airfoil wall portion 29. Preferably thesepedestals are disposed substantially along the longitudinal axis of theblade in spaced relation to provide the hollow airfoil with adequatestrength along its entire length.

In the preferred embodiment of the invention a coolant fluid opening 13is provided which extends through the shaft portion 14 and communicateswith the hollow passage 11 of the airfoil. It will be apparent thatother arrangements for the fluid ent y may be provided within the spiritof the invention as, for example, a longitudinal opening through theroot 16 of the blade which is in efiect a longitudinal continuation ofthe hollow portion 11 of the blade.

It will be noted from an examination of FIGURE 2 that the ribs 19 and 21are of a greater height at the central or thicker portions of theairfoil and are of a progressively lesser height toward the ed es of theairfoil so that the hollow passage 11 between the ribs 19 and 21 is ofsubstantially the same thickness across the width of the blade whereby auniform cooling effect is achieved.

The turbine blade shown in FIGURES l and 2 is cast by means of theso-called lost wax process. Broadly speaking, this process involvesforming the core shown in FIGURES 3, 4 and 5 which has the configurationof the hollow passage ll of the airfoil and the coolant fiuid entrypassage 13 through the stalk. A wax pattern is formed over this corewhich has the outer configuration of the turbine blade shown in FlGURE land the pattern is in vested. The refractory material of the investmentis then fired and the wax caused to flow or burn out to form a moldwhich includes a cavity having the configuration of the blade shown inFIGURE 1 having the core shown in FIGURE 3 positioned therein. Moltenmetal is then cast in the cavity. Finally, the core shown in FIGURE 3which is preferably formed of a caustic leachable, ceramic material isdissolved out to provide the completed turbine blade shown in FIGURE 1.

As is shown in FIGURE 3, the core consists of an airfoil passage portion24 and a fluid entry passage portion 26. The fiuid passage portion 2-6has elongated ends 23 and 3% which serve as core prints. Similarly, theend 31 of the airfoil passage portion is somewhat elongated so that italso may serve as a core print. As shown in FIGURE 5, the airfoilpassage portion 24 of the core is provided with a series of spacedgrooves 32 on the concave side and a series of spaced grooves 34 on theconvex side thereof. The grooves 32 and 34 will form the ribs 19 andrespectively of the turbine blade in the subsequent casting procedure.At equally spaced points 36, 38, and 42, sections of the core betweenadjacent grooves are removed so that openings are formed in the core atthe points 36, 353, 4d and 42. The purpose of these openings is to formthe pedestals 22 extending from the concave to the convex airfoil walls.Preferably the grooves 32 and 34 extend to a point somewhat short of thetop of the core so that in the resulting blade the end section of theblade is not ribbed.

The core shown in FIGURES 3, 4 and 5 is made as follows. A ceramic mixis provided which may be injection molded and which, on beingfired, willnot warp or shrink unduly and will be capable of withstanding thermalshock due to the molten metal being poured thereagainst in the castingprocess. Further the fired ceramic material lmust be capabl of beingleached .out or otherwise removed after the metal casting process.

A suitable composition for this purpose is a mixture containing oxidesof aluminum and silicon, a plasticizer and a binder such as polystyrene.Suitable commercial ceramic materials of this type are produced by theAmerican Lava Company and are known as Alsimag 145 and Alsimag 670. Aspecific example of a suitable ceramic mix consists by weight of 84parts of alumina, 5 parts shellac, 5 parts Ethocel, 0.2 parts stearicacid, 2 parts heater'oil, 2 parts butyl phthalate, 0.5 parts oleic acidand 2 parts n-butyl stearate. A suitable injection molding apparatus foruse in molding the core member shown in 3 is shown in FIGURES 6 through10 and forms a portion of this invention. Referring to FIGURE 6, theinjection molding apparatus includes a lower die block member mounted bymeans of bolt on a plate as for limited relative vertical movement. Theplate 46 is rigidly attached to a base 47. A vertically movable upperdie block member 48 is ass ciated with a plate 50 for a limited relativevertical movement.

As shown in FIGURE 10, the lower die block 44 includes a die 4-9 whichdefines the lower portion of the die cavity 51. The lower die 49includes a series of slots in which are retractably positioned a seriesof plates 52. The plates 52 are supported in spaced relation by the bar54 beneath the die block 24 and attached to the plate 45 by means of thebolts 1%. The plates 52 are of a length such that when the block 44-rests on the plate 46, the upper ends of the plates 52 project into thedie cavity 51 an amount equal to the epth of the grooves 32 of the coreas shown in FIGURE 5.

The upper die half 56 mounted in the upper die block 43 defines theupper or convex portion of the die cavity and has provided therethrougha series of spaced slots in which are positioned a series of retractableplates 53. The plates 58 are attached to the plate 56 by means of thebar it": and bolts 1% and are of a length such that when the blocks 44and 48 and the plates 45 and 50 are in an abutting position, the lowerends of the plates 58 project into the die cavity an amountcorresponding to the grooves 34 of the core as shown in FIGURE 5. One ofthe plates 52 in the lower die block 44 has elongated portions at spacedintervals which enter the space between a pair of plates 64 and 56 whenthe plat-es 58 are in a lowermost position and the plates 52 are in anuppermost position so as to provide the openings 36, 38, 4t and 42 inthe core.

A eferring to FIGURES 6 and 9, the injection mold apparatus includes aplate 65. attached for reciprocable movement to the rods 79 and a secondplate 74 reciprocably mounted on the rods 76 and the guide rods 75. Theguide rods 75 are attached to each corner of the upper die block andeach. rod slidably extends through an opening in the plate 74. The lowerplate 68 supports an injection cylinder 76. An injection opening "78 isprovided in the base of the injection cylinder 76 which extends throughthe plate 68. The base of the opening 78 is adapted to communicate withan injection opening 8% in the upper die block and plate 48 and 5%respectively when the plate 68 is in its lowermost position in contactwith the plate 5-8. The injection opening 30, of course, leads to thedie cavity 51 as shown in FIGUREIO.

The plate 74 supports a piston 32 which is adapted to operate within thecylinder 76. It will be readily apparent that when, as shown in FIGURE7, the die blocks 44 and are in a closed position and the plate 5% abutsthe die block 43, the plate 63 may be moved to a position of abutmentwith the plate 56 whereby the opening 78 of plate 68 is in communicationwith the injection opening 8d of the die block. Further in this positionthe plate 74 may be lowered so that the piston 82 attached thereto maysubject any moldable substance within the cylinder 76 to injectionmolding pressure so as to force the moldable material into the diecavity 51.

Referring again to FIGURES 6 and 9, the upper die block portion 43carries a pair of pivotally mounted hooks 84 and 36 which are adapted toengage a shoulder 8:3 in the lower die block 44 when the die blocks 44and 43 are in a fully closed position as shown in FIGURE 7. The plate 68normally rests on the plate 5%) of the upper die block 48 as shown inFIGURE 7. The plate 63 is shown in a raised position in FIGURES 6 and 9so as to better illustrate the apparatus. Compression coil springmembers 9% are disposed about the guide rods 7% through which pressureis imposed on the upper plate when the piston carrying plate '74 .islowered in an injection stroke into engagement with these coil springs.Similarly, coil springs 94 are disposed about the guide rods 75extending from the die block 48 for placing the die blocks 4-4 and 4dand the plate 46 under compression when the plate 74 is brought down ina compression stroke. The piston carrying plate 74 is attached to ahydraulically operated rod 102 by means of lugs 134. The hydraulic rod1&2 is operatively connected to a hydraulic piston (not shown) wherebythe piston carrying plate 74 may be reciprocated vertically to operatethe apparatus in an injection cycle as will be described in detailhereinafter.

As indicated above, the longitudinal plates 52 and 55 are attached tothe plates 46 and 5% respectively whereby a vertical movement of theseplates relative to the die blocks 44- and 48 respectively is effectivein inserting the ends of these bar members into the die cavity 55 andwithdrawing them therefrom. The bars 54 and 69 support the plates 52 and58 respectively in a parallel aligned position.

Referring to FIGURE 6, a pair of L-shaped cranks Mil and 112 areattached to cam shafts 114 and lie respectively journaled in the dieblock and supporting the die block 44 on the adjustable blocks 13% and 1.32 mounted on the plate 46. Pins 118 and 12%) attached to the cranks11d and 112 respectively extend into grooves 122 and 124 respectivelywithin the lower die block 44 which guide the movement of the cranks litand 112 respectively through an angle of 90. This )O" movement isillustrated in the difference in the positions of these members inFIGURES 6 and 7. FEGURE 6 shows the crank portions in a verticalposition whereas FIGURE 7 shows these crank portions in a horizontalposition. It will be noted that when the cranks tilt) and 112 are in avertical position, the cams 114 and 1155 support the die block 44 on around portion thereof so that the die block 44 is raised a shortdistance from the plate When the cranks T16 and 1 2 are moved to ahorizontal position as shown in FIGURE 7, the cams 114 and 116 supportthe die block 44 on their flat sides 126 and 128 whereby the block 44 isin a lowered position on the plate 4-5. it is readily apparent that whenthe die block 4% is in a raised position with respect to the plate as,the plates 52 are in a position retracted from the die cavity 51.

Similarly, the upper block 43 has the L-shaped cranks 134 and 136connected to cam shafts 138 and ldtl respectively. These cranks alsoinclu-e projecting pins 14-2 and 144 which ride in arcuate grooves 1%and 147 respectively whereby the cranks 134 and 136 may be moved throughan arc of 90. When in the upper position shown in FIGURE 6, the camshafts 138 and 1M3 support the plate St} on the round portions thereofso that the plates 58 are retracted from the mold cavity 51. When thecranks 134 and 136 are moved to a horizontal position as shown in FIGURE7, the cam shafts 138 and 145) are moved so that they support the plate59 on their flat sides 13% and 141 respectively.

The apparatus further includes a downwardly projectting arm 143 rigidlyconnected to the piston carrying plate 74 which has opposed horizontalprojecting detents 15-9 and 152. It may readily be seen that as the arm1 8 is moved downwardly, the detents 15d and 152 will move the cranks134 and 135 respectively through an angle of 90, and as the arm 148continues in its downward path, it will move the cranks lit and 112through an angle of At this time the mechanism will be in the positionshown in FIGURE 7. The cranks and 136 as well as the cranks lit? and 112are all in a horizontal position with the result that the plates 58 andthe plates 52 project into the mold cavity 5'1 as shown in FIGURE 10.When the arm 3148 is moved upwardly, the crank arms 11d and H2, 134 and136 are moved to a vertical position with the result that the plates 52and 58 are retracted from the mold cavity 51.

The complete operation of the core injection apparatus is as follows.The mold apparatus is assembled in an operating position when the lowerand upper die blocks 46 and 43 are clamped together by means of thehooks S4 and as and the cylinder carrying plate 68 rests on the upperdie block plate 56. In this position the cam shafts 3E and 1 h") supportthe plate 5% on their round portions and the cam shafts 114 and 116support the die block 44 on their round portions so that the plates 52and 58 are withdrawn from the die cavity 51. A preformed and preferablypreheated biscuit of the plasticized ceramic mix is placed in thecylinder 76 and hydraulic pressure is applied to the plate 74 by meansof the rod 1&2 to cause the plate 74 to descend. As the plate 74-descends, the arm 14% first progressively moves the then verticallydisposed cranks 134, 136, 119 and 112 into a horizontal position asshown in FTGURE 7 with the result that the cams lStl and support theplate 5%} on their fiat sides I39 and 141 respectively and the cams 114and 116 sup port the die block 44 on their fiat sides 1% and 128respectively so that the plates 52 and 58 are inserted into the diecavity in as shown in FIGURE 10. The crank arms, it will be observed,are locked in place by means of the pins I42, 144, 113 and 124) so thatthe subsequent injection of the ceramic mix does not alter the positionof these plates Within the cavity 51. Near the end of the downwardmovement of the plate 74 and after the cranks i3 4, 136, 11% and Illhave been moved to a horizontal position, the piston 82. is brought tobear down upon the biscuit to transfer the ceramic mix into the diecavity 51 through the sprue openings 7 3 and 8d. After the injection hasbeen completed, the plate 74 is raised and the cranks 134, 13-6, lid and112 are again moved to a vertical position. As the crank arms are movedto a vertical position, the cam members 114 and 116 again support thedie block 44 on their round portions and cam members 1355 and 1459support the plate 5% on their round portions so that the plates 52 andare withdrawn from the mold cavity. Thereafter the die blocks are openedand the core is dried and subsequently fired.

After the core has been formed, a pattern of destructible material iscast or otherwise formed about the core and the pattern is invested inthe refractory material in a manner well known in the art. The patternis preferably formed of a low temperature fusing substance such as waxor a thermoplastic synthetic resin or any other vaporizable, fusible,combustible or otherwise destructible material. However, a Wax orplastic pattern may be employed with optimum results. Among the plasticmaterials which are satisfactory for use as pattern material arepolystyrene and polymerized derivatives of acrylic and methacrylic acid.

The pattern is preferably formed by placing the fired core such as isshown in FIGURE 3 in an injection fixture (not shown) having a diecavityin the shape of the blade to be cast in which the core issupported by the end 31 of the airfoil portion 24 of the blade and thefluid entry end portions 25 and 3% which serve as core prints. Thepattern material is injected about the core to form a pattern identicalin shape to the cast blade shown in FIG- URE 1 wherein the blade portionis formed of the aforesaid pattern material and envelope the core.

The surfaces of the pattern are next coated with a ceramic wash orcoating material to provide a smooth casting surface on the refractorymold to be formed over this pattern. Preferably the coating materialcomprises an aqueous dispersion of conventional finely comminutcdrefractory materials, a binder such as an air-setting silicate cementand defoaming and wetting agents.

Coating of pattern with the ceramic wash is preferably accom lished bydipping the pattern into the coating solution. in some instances thecoating material may be applied by spraying or painting the coatin ontothe pattern. The dipping procedure is preferred because this methodassures a more uniform coating of all surface portions of the patternand is a simple method.

The dip coat slurry is preferably kept in a constant notion by stirringexcept during the actual dipping operation. The action should notunnecessarily introduce air into the slurry and care should be exercisedin the clipping operation to prevent air entrapment between thepatternand the coating. Preferably th dip coat solution'is maintained atroom temperature during the clipping operation since excessive heat mayresult in a distortion of the plastic or wax pattern. The excess coatingmaterial is permitted to drain ofi prior to investment of the pattern.

After the pattern has been completely cured with the dip coat slurry, itis preferably sanded. or stuccoed to provide a rough surface on thecoating which insures greater adhesion between the principal refractoryportion of the mold and the dip coat on the pattern. The sanding isaccomplished by merely screening or otherwise applying slica sand orother suitable refractory material to the dip coat of the destructiblepattern. Thereafter the coated pattern is air dried.

Following the preparation of the pattern as above indicated, aninvestment mold (not shown) containing a relatively coarse refractorymaterial is formed on the pattern. Suitable gating portions preferablymade of the same material as the pattern are attached to the pattorn andpermitted to extend through the. wall of the refractory mold to permitthe escape of the destructible pattern material and to form an ingatefor the molten casing metal. This refractory mold may be formed aboutthe pattern in any suitable manner and hence the procedure of forming itwill not be described in detail. A satisfactory procedure is that ofmixing the refractory mixture in a predetermined quantity of a liquidbinder, positioning the pattern within a suitable flask or sleeve andpouring the refractory mixture over the pattern and then allowing therefractory material to set. The refractory body may be formed of aconventional silica having an ethyl silicate binder or any othersuitable investment material. An example of an investment dry grog ormix which may be used is one comprising major proportions of a finelyground burned fire clay and silica flour and minor proportions ofmagnesium oxide and borax glass. The binder for this grog may include anaqueous solution of condensed ethyl silicate, ethyl alcohol andhydrochloric acid. In the process of forming the investment mold, theends 23, 3t! and 31 of the core which project beyond the destructiblepattern are embedded in the refractory material to provide a support forthe core within the refractory mold.

When the refractory mold material has solidified or set to a sufiicientextent, heat is applied thereto to melt the pattern. It is necessary toapply sufficient heat to raise the mold temperature above the fusionpoint of the pattern material, thus permitting the molten material ofthe pattern to escape through the gate in the mold.

Upon removal of the pattern from the mold in the foregoing manner, themolten casting metal is poured into the mold cavity formed by theremoval of the pattern material. After the molten metal has been pouredand the casting solidified, the refractory mold body is broken away topermit removal of the castin". The casting is then immersed in asuitable solvent solution whereby the core material contained in thecast body is dissolved or leached out. A suitable leaching agent forthis purpose is a molten reducing salt such as the Kolene salt producedby the Kolene Corporation which requires no venting precautions and willnot adversely react with the casting metal.

The hollow configuration of the turbine blade of this invention providesit with satisfactory strength and a highly efficient cooling effect. Inthe event that the cooling rate is excessive, the size of the coolingpassages may be accurately and efi'iciently reduced by subjectingappropr ate portions of the core to a suitable solvent solution. it hasbeen found that an acid solution consisting of 100 milliliters of 52% to55% hydrofluoric acid and 600 milliliters of 36% hydrochloric acid willremove about 0.004 inch from each side of the core in a period of threeminutes at about 150 F. Portions of the core which are not to besubjected to the solvent solution may be protected by a suitablestop-off agent.

While the present invention has been described by means of certainspecific examples, it will be understood that the scope of the inventionis not to be limited thereby except as defined in the following claims.

I claim:

1. Core making die apparatus comprising, in combination, first andsecond complementary die block members defining a die cavitytherebetween, a plurality of first elongated core plates retractablyextending through said first die block into said cavity and a pluralityof second elongated core plates retractably extending through said dieblock into said cavity, first movable plate means attached to each ofsaid first core plates, a second movable plate means attached to each ofsaid second core plates, first cam means for supporting said first platemeans in a first position whereby said first core plates are retractedfrom said die cavity and for supporting said first plate means in asecond position whereby said first core plates extend into said diecavity a predetermined amount, second cam means for supporting saidsecond plate means in a first position whereby said second core platesare in a retracted position and for supporting said second plate meansin a second position whereby said second core plates extend into saiddie cavity a predetermined amount, piston means for injecting a plasticmaterial into said cavity, means operatively connected to said pistonmeans for sequentially operating said first and second cam means tocause said core plates to project into said cavity when said pistonmeans is actuated to inject plastic material into said cavity.

2. Core making apparatus comprising in combination, first and secondcomplementary die block members defining a cavity thcrebetween, aplurality of first elongated core plates retractably extending throughsaid first die block into said cavity and a plurality of secondelongated core plates retractably extending through said second dieblock into said cavity, a first movable plate means attached to each ofsaid first core plates, a second movable plate means attached to each ofsaid second core plates, 21 first cam means for supporting said firstplate means in a first position whereby said first core plates areretracted from said cavity and for supporting said first plate means ina second position whereby said first core plates extend into said diecavity a predetermined amount, a second cam means for supporting saidsecond plate eans in a first position whereby said second core platesare in a retracted position and for supporting said second plate meansin a second position whereby said second core plates extend into saiddie cavity a predetermined amount, piston means for injecting a plasticmaterial into said cavity, crank means for actuating each of said cammeans to support said first and second core plates between said firstand second positions, an arm means operatively connected to said pistonmeans movable with the movement of said piston for sequentiallyoperating said crank means to cause said core plates 9 to project intosaid cavity when said piston means is actuated to inject plasticmaterial into said cavity.

3. Core making apparatus comprising in combination, first and secondcomplementary die block members defining a cavity therebetween, aplurality of first elongated core plates retractably extending throughsaid first die block into said cavity and a plurality of secondelongated core plates retractably extending through said second dieblock into said cavity, a first movable plate means attached to each ofsaid first core plates, a second movable plate means attached to each ofsaid second core plates, a first cam means for supporting said firstplate means in a first position whereby said first core plates areretracted from said cavity and for supporting said first plate means ina second position whereby said first core plates extend into said diecavity a predetermined amount, a second cam means for supporting saidsecond plate means in a first position whereby said second core platesare in a retracted position and for supporting said second plate meansin a second position whereby said second core plates extend into saiddie cavity a predetermined amount, piston means for injecting a plasticmaterial into said cavity, crank means for actuating each of said cammeans to support said first and second core plates between said firstand second positions, an arm means operatively connected to said pistonmeans movable with the movement of said piston for sequentiallyoperating said crank means to cause said core plates to project intosaid cavity when said piston means is actuated to inject plasticmaterial into said cavity and for operating said crank means in reversesequence to cause said core plates to be retracted from said cavity whensaid piston means is actuated in the reverse direction.

4. Core making apparatus comprising in combination first and secondcomplementary die block members defining a die cavity therebetween, aplurality of elongated core plates retractably extending through one ofsaid die blocks into said cavity, a movable plate means attached to eachof said core plates, a cam means for supporting said plate means in afirst position whereby said core plates are retracted from said diecavity and for supporting said plate means in a second position wherebysaid core plates extend into said die cavity a predetermined amount,piston means for injecting a plastic material into said cavity and meansoperatively connected to said piston means for operating said cam meansto cause said core plates to project into said die cavity when saidpiston means is actuated to inject plastic material into said cavity.

5. Core making apparatus comprising in combination first and secondcomplementary die blocks disposed vertically one over the other defininga die cavity therebetween, a plurality of first elongated core platesvertically and retractably extending through said first die block intosaid cavity and a plurality of second elongated core plates verticallyand retractably extending through said second die block into saidcavity, a first movable plate means attached to each of said first coreplates, a second movable plate means attached to each of said secondcore plates, a first cam means for supporting said first plate means ina first vertical position whereby said first core plates are retractedfrom said die cavity and for supporting said first plate means in asecond vertical position whereby said first core plates extend into saiddie cavity a predetermined amount, a second cam means for supportingsaid second plate means in a first vertical position whereby said secondcore plates are in a retracted position and for supporting said secondplate means in a second vertical position whereby said second coreplates extend into said die cavity a predetermined amount, piston meansmounted over the uppermost die block for injecting a plastic materialinto said cavity, and a vertically disposed arm means operativelyconnected to said piston means for sequentially operating said first andsecond cam means to cause said core plates to project into said cavitywhen said piston means is moved vertically downwardly to inject plasticmaterial into said cavity.

References (Iited by the Examiner UNITED STATES PATENTS 417,591 12/89Serve 22-13 928,786 7/09 McNamara 22-50 1,187,027 6/16 Bates 22-131,347,080 7/20 Clark 22-13 1,378,524 5/21 Clark 22-13 1,968,703 7/34Peyinghaus 22-10 2,278,190 3/42 Bodi 22-10 2,474,186 6/49 Marks 22-1652,688,781 9/54 Fahlberg et al. 22-165 2,749,586 6/56 Kohl et al. 22-1942,829,409 4/58 Frommer 22-93 2,835,006 5/58 Fourden et al. 22-93 MICHAELV. BRINDISI, Primary Examiner.

5o MARCUS U. LYONS, Examiners.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,192,58 Jul-y 6, 1965 Hamilton Le McCormick It is hereby certified that errorappears in the above numbered patent requiring correction and that thesaid Letters Patent should read as corrected below.

In the grant (only) line name, 9 inVeIIIQT, for "Hamilton L. McCormic"read Hamilton LC McCormick column 7, line 28, for "slica" read silicaline 38, for "casing" read casting column 8, line 29, before "die insertsecond Signed and sealed this 28th day of December 1965.

(SEAL) Attest:

ERNEST W. SWIDER Attesting Officer EDWARD J. BRENNER Commissioner ofPatents

1. CORE MAKING DIE APPARATUS COMPRISING, IN COMBINNATION, FIRST ANDSECOND COMPLEMENTARY DIE BLOCK MEMBERS DEFINING A DIE CAVITY THEREBETWEEN, A PLURALITY OF FIRST ELONGATED CORE PLATES RETRACTABLY EXTENDINGTHROUGH SAID FIRST DIE BLOCK INTO SAID CAVITY AND A PLURALITY OF SECONDELONGATED CORE PLATES RETRACTABLY EXTENDING THROUGH SAID DIE BLOCK INTOSAID CAVITY, FIRST MOVABLE PLATE MEANS ATTACHABLE TO EACH OF SAID FIRSTCORE PLATES, A SECOND MOVABLE PLATE MEANS ATTACHED TO EACH OF SAIDSECOND CORE PLATES, FIRST CAM MEANS FOR SUPPORTING SAID FIRST PLATEMEANS IN A FIRST POSITION WHEREBY SAID FIRST CORE PLATES ARE RETRACTEDFROM SAID DIE CAVITY AND FOR SUPPORTING SAID FIRST PLATE MEANS IN ASECOND POSITION WHEREBY SAID FIRST CORE PLATES EXTEND INTO SAID DIECAVITY A PREDETERMINED AMOUNT, SECOND CAM MEANS FOR SUPPORTING SAIDSECOND PLATE MEANS IN A FIRST POSITION WHEREBY SAID SECOND PLATE MEANSIN A RETRACTED POSITION AND FOR SUPPORTING SAID SECOND PLATE MEANS IN ASECOND POSITION WHEREBY SAID SECOND CORE PLATES EXTEND INTO SAID DIECAVITY A PREDETERMINED AMOUNT, PISTON MEANS FOR INJECTING A PLASTICMATERIAL INTO SAID CAVITY, MEANS OPERATIVELY CONNECTED TO SAID PISTONMEANS FOR SEQUENTIALLY OPERATING SAID FIRST AND SECOND CAM MEANS TOCAUSE SAID CORE PLATES TO PROJECT INTO SAID CAVITY WHEN SAID PISTONMEANS IS ACTUATED TO INJECT PLASTIC MATERIAL INTO SAID CAVITY.